EP0782029A1 - Optische Vorrichtung wie etwa ein optischer Zirkulator und Isolator - Google Patents

Optische Vorrichtung wie etwa ein optischer Zirkulator und Isolator Download PDF

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Publication number
EP0782029A1
EP0782029A1 EP96308959A EP96308959A EP0782029A1 EP 0782029 A1 EP0782029 A1 EP 0782029A1 EP 96308959 A EP96308959 A EP 96308959A EP 96308959 A EP96308959 A EP 96308959A EP 0782029 A1 EP0782029 A1 EP 0782029A1
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EP
European Patent Office
Prior art keywords
polarization
beams
walk
devices
optical apparatus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96308959A
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English (en)
French (fr)
Inventor
Ernest Eisenhardt Bergmann
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Nokia of America Corp
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Lucent Technologies Inc
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Publication of EP0782029A1 publication Critical patent/EP0782029A1/de
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/09—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on magneto-optical elements, e.g. exhibiting Faraday effect

Definitions

  • This invention relates generally to the field of optical devices and particularly to the field of optical devices, such as circulators and isolators, that are useful in optical communications systems.
  • Optical communications systems require apparatus that manipulates optical signals that are in the form of light rays.
  • the best known apparatus for such manipulation at the present time is probably the ubiquitously used silica based optical fiber which is used for both short and long distance optical transmission.
  • other well known apparatus includes the couplers and multiplexers that have been developed to couple one or more optical signals into one or more optical fibers or waveguides.
  • Some applications desirably use nonreciprocal apparatus or devices and such devices have been developed; of course, not all optical devices are nonreciprocal.
  • Nonreciprocal means that the propagation characteristics of light within the apparatus depends upon the direction of light propagation within the apparatus.
  • optical isolator permits light to pass through the apparatus in one direction but not in the reverse direction.
  • optical circulator Another type of such nonreciprocal apparatus is termed an optical circulator; this device has 3 or more ports which permit light to pass from a first to a second port but not from the second port to the first port; instead light entering the second port passes to a third port.
  • An isolator may be thought of as a two port circulator; however, the term isolator is the preferred term.
  • optical devices including the circulators and isolators briefly described in the previous paragraph, have been developed for commercial applications.
  • the device should be polarization independent to the external world; that is, device operation should not depend upon the polarization of the incoming light.
  • Fujii in Journal of Lightwave Technology, 10, pp. 1226-1229, September 1992, describes a polarization independent apparatus that he states can be used as an optical circulator.
  • the apparatus is schematically depicted in his FIG. 1. Although stated to be useful over a wide range of wavelengths, preferred operation of the apparatus depends upon precise orientation of the components with respect to each other.
  • Another optical circulator is described by Koga in United States Patent 5,204,771 issued April 20, 1993.
  • Koga's circulator appears to be the use of a birefringent plate followed by nonreciprocal optical rotators.
  • the birefringent plate splits the incoming beam into two parallel beams and the optical rotators change the polarizations of each of the two beams by 45 degrees so that there are two parallel beams with orthogonal polarizations.
  • the Fujii circulator depends upon precise relative orientation of the components; this orientation may be difficult to achieve in practice and still more difficult to maintain for extended periods of time.
  • the Koga device is extremely complicated. The complexity arises not only because there are many components, but also because the large number of components necessarily has a large number of surfaces. Any one of these surfaces can produce undesired reflections.
  • the devices must be designed to either eliminate the reflections or to compensate for them.
  • the optical rotators must be precisely aligned so that one beam passes through the top half of the rotator and the other beam passes through the bottom half of the rotator. The small beam sizes and small separation of the beams will likely make this difficult.
  • an optical device has at least a first walk-off device that either separates an incoming beam into two outgoing mutually parallel beams of orthogonal polarization or combines two mutually parallel incoming beams of orthogonal polarization into a single outgoing beam, and at least a first polarization flipper positioned to change the polarization of one of the two outgoing beams to match the polarization of the other outgoing beam from the first walk-off device or to change the polarization of one of the incoming beams.
  • a nonreciprocal section is positioned to receive the two beams.
  • the polarization may be linear or elliptical including circular as a particular case.
  • the device may also have a second walk-off device, and a second polarization flipper that combine the two beams from the combination of first walk-off device and first polarization flipper.
  • the combination of the first walk-off device and the first polarization flipper, as well as the combination of the second walk-off device and the second polarization flipper, may or may not contain nonreciprocal elements. Additional elements, possibly including nonreciprocal elements, may be included.
  • the invention will be described by reference to the exemplary embodiment depicted in FIG. 1.
  • Shown in FIG. 1 are walk-off device 1 and polarization flipper 3.
  • the direction of propagation of the incoming beam is designated by the arrow; the walk-off device splits the incoming beam into ordinary and extraordinary beams which are designated as O and E, respectively.
  • the incoming beam enters the device at port 5 which is adapted to receive the incoming light and functions as an input.
  • the E beam passes through the polarization flipper 3.
  • the E component is changed into O and there are two parallel O beams.
  • the two O beams exiting from the device are parallel and have parallel polarizations after polarization flipping.
  • the walk-off device may be fabricated from a birefringent material such as calcite or rutile; such materials are well known and the walk-off device will be readily fabricated by those skilled in the art as will the polarization flipper.
  • the device may also be operated as a polarization combiner with the two O beams going from right to left and entering the device on the right side.
  • the polarization flipper is now used so that the O component is changed into E when combining.
  • the walk-off device 1 then walks the E and O beams(one O beam has been changed to E polarization by polarization flipper 3) together so that both beams combine and exit at port 5 which now functions as an output.
  • the device depicted may be termed an OPSOC which is an acronym for "O Polarization Splitter Or Combiner.”
  • the polarization flipper may flip the polarization of the O ray exiting from the first walk-off device; such a device in depicted in FIG. 2.
  • the device is similar to that depicted in FIG. 1 except that the two outgoing beams are E beams because the O beam passes through the first polarization flipper 3. Accordingly, the device is conveniently referred to as an EPSOC which is an acronym representing "E Polarization Splitter Or Combiner.”
  • the EPSOC device is generally similar to the OPSOC device; however, the polarization flipper is used to change the O polarization component into E when splitting and to change the E polarization component into O when combining.
  • the devices depicted in FIGs. 1 and 2 may be used individually or they may be combined, possibly with other elements, in yet more complicated devices.
  • a nonreciprocal section is positioned to receive the two beams.
  • Such a device is shown in FIG. 3 and and incorporates first and second OPSOC devices as depicted in FIG. 1 as well as the EPSOC device depicted in FIG. 2.
  • the EPSOC device is between the first and second OPSOC devices.
  • the first and second OPSOC devices are formed by walk-off device 21 and polarization flipper 23 and by second walk-off device 31 and second polarization flipper 33, respectively.
  • the first and second OPSOC devices are Faraday rotator 51 and half wave plate 53 as well as EPSOC device having a walk-off device 41 and a polarization flipper 43.
  • An alternative embodiment uses two EPSOC devices and an OPSOC device between the two EPSOC devices. As shown here, the walk-off devices are oriented so that the walk-off direction is either into or in the plane of the paper.
  • the device has three ports which are shown as A, B and C. Light is transmitted from port B to port C and from port C to port A.
  • the device is a partial circulator(there is no light transmission from port A to port C), but in accordance with current terminology will be referred to as a circulator.
  • the Faraday rotator is used in conjunction with a magnetic field that is either approximately parallel to the beam direction or approximately anti-parallel to the beam direction.
  • a magnetic field that is either approximately parallel to the beam direction or approximately anti-parallel to the beam direction.
  • the amount of rotation of the plane of polarization for a given thickness of material can be readily determined. Reversing the direction of the beam propagation without a corresponding reversal of the direction of the magnetic field will cause the rotation direction of the plane of polarization to be in the opposite sense.
  • a thickness of the material so that the amount of rotation is about 45 degrees, useful, non-reciprocal behavior can be obtained with the use of a polarization rotator as the suitably oriented half-wave plate 53. If the plate 53 is oriented to also rotate the plane of polarization 45 degrees, then a beam passing in one direction thought the combination of elements 51 and 53 will experience a polarization flip whereas the beam will experience no change in the reverse direction. This behavior can be achieved without requiring that elements 51 and 53 be in contact with each other and can be achieved even with element 51 following element 53. Of course, one could use optical activity instead of birefringence for element 53.
  • the operation of the circulator depicted in FIG. 3 is now readily understood. Light propagation from port C to port A will be described.
  • the unpolarized incoming beam enters walk-off device 21 at port C and is separated into O and E polarized beams as shown.
  • the E beam has its polarization flipped by polarization flipper 23 so that the polarizations of both beams are now parallel.
  • the beams pass through the combination of elements 51 and 53 and, by the assumptions made above for purposes of exposition, the polarizations of both beams are flipped by 90 degrees.
  • the two beams then enter the walk-off device 41 of the EPSOC device as O-polarized beams with respect to 41 and travel through walk-off device 41 as shown by the solid lines and enter polarization flipper 43. If the beams had possessed the other polarization when entering walk-off device 41, they would have walked-off as extraordinary beams out of the plane of the paper as shown by the dotted lines.
  • the lower beam passes through the second polarization flipper 33 so that it is E-polarized with respect to the second walk-off device 31 and this device walks these two beams together so that both exit from port A.
  • Port B is out of the plane of the paper as indicated by the dotted lines going from right to left.
  • the unpolarized beam is split into O and E polarization components by walk-off device 31 and polarization flipper 33 flips the polarization of the lower beam.
  • Both beams, being out of the plane of the paper, pass around polarization flipper 43.
  • the two beams are E polarized relative to walk-off plate 41 and so are walked back into the plane of the paper.
  • the E polarized beams relative to 41 are then passing through the nonreciprocal combination of elements 51 and 53 where they are assumed to not have their polarizations flipped. They are O polarized with respect to walk-off plate 21.
  • the upper beam has its polarization flipped to E by polarization flipper 23 and walk-off plate 21 then walks the two beams together so that they both exit at port C.
  • the term walk-off device is used to mean any device that yields parallel beams with orthogonal polarizations.
  • the polarization flipper may be implemented by other means such as by Faraday rotation or by optical activity.
  • the polarizations may or may not be parallel/perpendicular to the beam separation direction.
  • the invention includes embodiments that are not characterized as either EPSOC or OPSOC. These embodiments may be referred to as LPSOC which is the acronym for "Like Polarization Splitter Or Combiner.”
  • LPSOC is the acronym for "Like Polarization Splitter Or Combiner."
  • a preferred embodiment may require that the first OPSOC and second OPSOC be relatively inverted such as depicted in FIG. 3.
  • This embodiment helps to equalize the optical path lengths and hence minimize polarization mode dispersion(PMD) as well as polarization dispersion loss(PDL).
  • PMD polarization mode dispersion
  • PDL polarization dispersion loss

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
EP96308959A 1995-12-26 1996-12-10 Optische Vorrichtung wie etwa ein optischer Zirkulator und Isolator Withdrawn EP0782029A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US578721 1995-12-26
US08/578,721 US5729377A (en) 1995-12-26 1995-12-26 Optical apparatus

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002029473A1 (fr) * 2000-10-03 2002-04-11 Fdk Corporation Circulateur optique et commutateur optique
WO2016085847A1 (en) * 2014-11-26 2016-06-02 Nistica, Inc. Launch optics with optical path compensation for a wavelength selective switch

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0990279A (ja) * 1995-09-20 1997-04-04 Nec Corp 偏光無依存型光アイソレータと光サーキュレータ
US6163393A (en) 1996-10-29 2000-12-19 Chorum Technologies Inc. Method and apparatus for wavelength multipexing/demultiplexing
US6115155A (en) 1996-10-29 2000-09-05 Chorum Technologies Inc. System for dealing with faults in an optical link
US6847786B2 (en) 1996-10-29 2005-01-25 Ec-Optics Technology, Inc. Compact wavelength filter using optical birefringence and reflective elements
US6243200B1 (en) 2000-03-02 2001-06-05 Chorum Technologies, Inc. Optical wavelength router based on polarization interferometer
US6545783B1 (en) 1996-10-29 2003-04-08 Chorum Technologies Lp Optical wavelength add/drop multiplexer
US6026202A (en) * 1997-02-25 2000-02-15 Hewlett-Packard Company Compact, low crosstalk, three-port optical circulator
US6239900B1 (en) 1997-09-19 2001-05-29 Nz Applied Technologies Corp. Reflective fiber-optic isolator
US5909310A (en) * 1997-12-08 1999-06-01 U.S.A Kaifa Technology, Inc. Optical circulator
US5930039A (en) * 1997-12-08 1999-07-27 U.S.A Kaifa Technology, Inc. Optical circulator
US6049426A (en) * 1998-08-17 2000-04-11 New Focus, Inc. Compact polarization insensitive circulators with simplified structure and low polarization mode dispersion
US6175448B1 (en) 1998-08-17 2001-01-16 New Focus, Inc. Optical circulators using beam angle turners
US6430337B1 (en) 1998-09-03 2002-08-06 Agere Systems Optoelectronics Guardian Corp. Optical alignment system
US6154581A (en) * 1998-10-27 2000-11-28 Adc Telecommunications, Inc. Multiple port, fiber optic circulator
US6212008B1 (en) 1998-11-13 2001-04-03 New Focus, Inc. Compact polarization insensitive circulators with simplified structure and low polarization mode dispersion
US6519060B1 (en) 1999-06-04 2003-02-11 Chorum Technologies Lp Synchronous optical network in frequency domain
US6289153B1 (en) 1999-09-30 2001-09-11 Agere Systems Optoelectronics Guardian Corp. Laser aided tilt adjustment of an optical lens
US6822793B2 (en) 1999-10-29 2004-11-23 Finisar Corporation Compact polarization insensitive circulators with simplified structure and low polarization mode dispersion
US6442310B1 (en) * 2000-07-14 2002-08-27 Jds Uniphase Inc. Optical coupling device and method
US6515786B1 (en) 2001-08-03 2003-02-04 Chorum Technologies Lp Bandwidth variable wavelength router and method of operation
RU2603229C1 (ru) * 2015-07-08 2016-11-27 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр Институт прикладной физики Российской академии наук" (ИПФ РАН) Изолятор фарадея для неполяризованного лазерного излучения

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178073A (en) * 1977-05-31 1979-12-11 Nippon Electric Co., Ltd. Optical isolator
US4492436A (en) * 1983-01-03 1985-01-08 At&T Bell Laboratories Polarization independent beam splitter
US5204771A (en) 1990-12-17 1993-04-20 Nippon Telegraph And Telephone Corporation Optical circulator
EP0574749A2 (de) * 1992-06-19 1993-12-22 Mitsubishi Gas Chemical Company, Inc. Polarisationsunabhängiger optischer Isolator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4974944A (en) * 1988-07-21 1990-12-04 Hewlett-Packard Company Optical nonreciprocal device
US5251057A (en) * 1989-10-13 1993-10-05 Xerox Corporation Multiple beam optical modulation system
US5267078A (en) * 1990-12-20 1993-11-30 Kazuo Shiraishi Optical isolator
AU644044B2 (en) * 1991-02-20 1993-12-02 Sumitomo Electric Industries, Ltd. Optical isolator
JP3160319B2 (ja) * 1991-07-25 2001-04-25 株式会社信光社 光アイソレータ
US5414541A (en) * 1993-06-01 1995-05-09 Bell Communications Research, Inc. Optical switch employing first and second ferroelectric cells with alignment layers having alignment directions offset by 45°
US5436755A (en) * 1994-01-10 1995-07-25 Xerox Corporation Dual-beam scanning electro-optical device from single-beam light source

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178073A (en) * 1977-05-31 1979-12-11 Nippon Electric Co., Ltd. Optical isolator
US4492436A (en) * 1983-01-03 1985-01-08 At&T Bell Laboratories Polarization independent beam splitter
US5204771A (en) 1990-12-17 1993-04-20 Nippon Telegraph And Telephone Corporation Optical circulator
EP0574749A2 (de) * 1992-06-19 1993-12-22 Mitsubishi Gas Chemical Company, Inc. Polarisationsunabhängiger optischer Isolator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
FUJII., JOURNAL OF LIGHTWAVE TECHNOLOGY., vol. 10, September 1992 (1992-09-01), pages 1226 - 1229

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002029473A1 (fr) * 2000-10-03 2002-04-11 Fdk Corporation Circulateur optique et commutateur optique
US7050232B2 (en) 2000-10-03 2006-05-23 Fdk Corporation Optical circulator and optical switch
WO2016085847A1 (en) * 2014-11-26 2016-06-02 Nistica, Inc. Launch optics with optical path compensation for a wavelength selective switch

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Publication number Publication date
US5729377A (en) 1998-03-17
JPH09189885A (ja) 1997-07-22

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